Monitor windvane control lines. How far from rudder stock to attachment on tiller?

[Herreshoff]

I've installed my wonderful second hand monitor vane after a bit of welding and fiddling about. It's working reasonably well inshore and will test it properly on a long leg in the next week or so. I was wanting to know the distance people connect their control lines from the rudder stock with a tiller instillation. The monitor site says 'between 20'-30' . Clearly the closer to the rudder stock, the more sensitive the course correction changes, though a higher energy is needed as there is less leverage. I know that on certain angles of sail it would be better to have it closer or further depending. So that, on a reach or down wind it's better to have faster and larger course adjustments while upwind less (further from the rudder) would be preferable. I have mine at around 27' at the moment yet am considering reducing the distance. It's also a little ambiguous as to where I am measuring from as I have an stern hung rudder.

Could someone that has a servo pendulum set up help me on this one? What is the distance on yours? I know most folks are using wheels now so hope I can find someone with a tiller set up.

[UNCIVILIZED]

It is a curious question, especially as earlier today I saw one online that was connected to a 1' long sub-tiller, which was directly underneath of the regular tiller. Which was a new one to me.
Does not how much mechanical advantage the self steering has also depend on the lengths of the different parts of the line connecting it to the tiller or wheel?

[Paul Elliott]

My Monitor is connected to the wheel, not a tiller, so I can't give you any specifics. But you should swing the Monitor oar by hand over it's complete range and note how much the control line moves. Pick a tiller attachment point so this amount of control line gives you all the rudder angle you want. You usually want your boat balanced so the rudder is nearly centered and doesn't need a lot of tiller sweep, but you do want to give the Monitor enough range of control to be able to bring you back on course after (say) you get pushed around by a big wave.

The length(s) of the control line has no effect on the mechanical advantage, but the tiller attachment point, and the control-line-to -tiller angles does.

[Herreshoff]

Thanks Paul, that is helpful.
I will move the connection back towards the rudder approx. 5 inches and see how that effects things. It has been working responsibly well it's just a fine adjustment that needs to be made. Especially seems reaching and downwind in my preferred points of sail.

Thanks everyone.

[Paul Elliott]

Also, look at the Monitor manual (http://www.selfsteer.com/pdfs/MonitorManual.pdf). They recommend a trying a tiller attachment point about 30 inches from the rudder post. See section 3.5 in the manual for the details.

[double u]

cannot contribute the distance from the rudderaxis any more (forgotten), only that we used one fixed point & never altered it

[UNCIVILIZED]

A trick I saw ages ago just came to mind. On a boat or three that I've seen, things were setup where there was a piece of aluminum track mounted atop the tiller. And it had a series of holes running down it's length. With the lines that go to the vane connected to a quick release pin, which then was inserted into a hole in the track. That way it let them move the pin around a bit, thus altering the length of the lever arm which the vane was working with/against, based on; wind & sea conditions, course, & what sails were up.

I can't recall them saying how well it worked or didn't, but possibly it's an option. One which may be worth running by Scanmar, & other vane makers. And sadly I don't have my texts on building vanes around, or I'd look some of this stuff up.

[Paul Elliott]

In the manual I posted the link to (above), Scanmar mentions the adjustable track-mount for the tiller control line attachment. They say it may be useful.